I looked up the new Arizona law, and it says:
FOR ANY LAWFUL CONTACT MADE BY A LAW ENFORCEMENT OFFICIAL OR AGENCY OF THIS STATE OR A COUNTY, CITY, TOWN OR OTHER POLITICAL SUBDIVISION OF THIS
STATE WHERE REASONABLE SUSPICION EXISTS THAT THE PERSON IS AN ALIEN WHO IS UNLAWFULLY PRESENT IN THE UNITED STATES, A REASONABLE ATTEMPT SHALL BE MADE, WHEN PRACTICABLE, TO DETERMINE THE IMMIGRATION STATUS OF THE PERSON. THE PERSON'S IMMIGRATION STATUS SHALL BE VERIFIED WITH THE FEDERAL GOVERNMENT PURSUANT TO 8 UNITED STATES CODE SECTION 1373(c).
I also researched legal opinions regarding the enforcement of 8 United States Code Section 1373 C, and I found a very reasonable argument by Michael Lindsay, the director, at the Law Enforcement Academy of Indiana, from which I quote:
"Since a U.S. citizen stopped by a policeman is not required by either federal or state law to carry paperwork showing a right to be in the country, there is no obligation for a U.S. citizen to prove he is not an illegal alien. Even an illegal alien is not required to incriminate himself for a state criminal law violation. He is, of course, required to show a drivers license if driving on a public highway or a registration if in possession of a vehicle.
It is assumed by many protesters that this law is some type of civil procedure for taking illegal aliens into custody for a deportation hearing. The law allows for cooperation between the federal government and the state, but it does not make the state a deportation hearing board. That authority is specifically assigned to the federal government."
AND
"On the surface, the Arizona law appears to create a Gestapo-like system, e.g., “show me your papers”. This particular statute hits a hot button because it seems to have a racial component woven covertly into the fabric of the law. A closer examination, however, reveals that it does not require citizens to carry citizenship papers; it does not allow racial profiling; the burden of proof (because it is a criminal law) is on the state; and claiming that someone is an illegal alien must be certified through the federal government.
Other than the unfortunate effects of the media frenzy and the resulting boycott of Arizona businesses (which probably hurts Hispanic employees more than any other group), a genuine, open, long overdue discussion of federal-state responsibilities in this area is a likely consequence of the intense publicity generated by this law."
http://www.in.gov/ilea/2397.htm--------------------
My comment: As a non-US citizen who is seeking legal entry into the US, by waiting patiently for my visa, I think this law is very good. It should clear out the law breakers, and allow those who are trying to enter via legal means to do so.